Atlanta police inexplicably waited nine days to question a key witness to officers’ misconduct in the 2006 killing of 92-year-old Kathryn Johnston, according to a new investigative report. Instead, they put on a full-court press to track down an informant who corrupt officers wanted to use as their alibi. Cris Beamud, director of a city oversight panel created after the Johnston shooting, says police should find out why it took so long.